The comet next time
by Michael H. Brown
"The asteroid that hits earth may be in there," said Dr. Paul Chodas.
We were standing in a small cramped room at NASA's Jet Propulsion Laboratory in Pasadena. I was there to find out about the comet threat. He was pointing to several small box-like racks -- a shockingly makeshift compilation of radar images that could one day be the center of urgent international attention. With us was Dr. Eleanor Helin, the astronomer who heroically began some of the first official searches.
I was concerned because there had been recent "near-misses" with comets or asteroids that no one knew were coming. In 1989 an asteroid had missed earth by six hours. There had also been close buzzes in 1992, 1993, and 1994. In 1994 there was also the Shoemaker-Levy comet that hit Jupiter in 21 fragments (the most spectacular on July 16, feast day of the Virgin of Carmel, which is how Mary appeared during the last apparition at Fatima). And three years after that the Hale-Bopp comet hung in the sky for all to see.
That one was 30 to 40 miles wide, according to Chodas -- plenty big enough to destroy life on earth. And what bothered me was that it was discovered by amateur astronomers just 40 months before its closest pass.
Scientists have no idea when the next such comet will show up. There are two major comet belts, and one alone is suspected of containing more than 200 million comets. That's the current guess. Many are "long-term" comets that are more dangerous than asteroids (space rocks that don't glow) because they're winging in from a longer distance. That's saying a lot when you consider that asteroids often move at eight times the speed of a bullet! Long-term comets make their orbits over such a long period that they're not in the history books and could surprise us by coming from a blindspot behind the sun.
Is this in any prophecies? Will there one day be at least a regional event? Does it relate to what Revelation 8:8 said about "something like a huge mountain all in flames" that one day would be "cast into the ocean"?
According to astronomers it wouldn't take much of a rock to disrupt our planet. They say anything half-a-mile wide or larger would kick up enough dust to shut down global agriculture.
Even in the middle of the ocean, such an object would cause a wave that would be 35 feet when it reached the coasts, and one that was several times larger would cause a crater at the bottom of the ocean and send waves all the way to the Appalachian foothills.
Yet as Dr. Helin and others pointed out, very little of the sky is monitored. She told me she was convinced earth had been hit more frequently in the past than we know, and that astronomers should study folklore as well as the Bible for such evidence.
Some believe objects struck in the times of the ancient Egyptians, causing swerves in climate around 2500 B.C. and 1000 B.C., then again around 550 A.D. -- at the end of the Roman Empire. There are accounts from New Zealand of ancient fireballs and more recent encounters in South America. In 1178 a monk named Gervase of Canterbury watched an object strike the moon on the Sunday before the feast of John the Baptist. The Middle Ages, at the time of bubonic plague, was also a time of comets.
"For a long time we pooh-poohed and discouraged this sort of speculation because we would have just a little bit of information here and there, just a trace, and we would push it off the table," Dr. Helin told me. "But the more I see, the more I think there's an awful lot out there that we've ignored for an awful long time."
The long-term comets, says Helin, are the "stealth bombers in the solar system, the ones that give no warning, that are just there in your face." She said there have been times when she thought something would hit. "You put down the phone and say, `what do I do now?" she remarked of several unpublicized asteroid scares.
Scientists believe that there are bands of debris that periodically bombard earth. They're at the very root of the word "disaster," which means "evil star" (etymologically, dis-evil and aster-star). And space is filled with them. At one stage last year new asteroids were being discovered at a rate of 24 a month! By the end of the 1990s NASA had logged 1,076 near-earth objects that are either earth-crossers or come close to intersecting our orbit -- of which 405 were a kilometer or larger.
Even if we knew something was going to hit, I was told by Dr. Brian Marsden of Harvard, it would take us 15 to 20 years to devise a way of destroying it.
Some say we're centuries away from having to worry about that, while others warn that a cycle of strikes will result by 2300 from what's called the Taurid belt. And still others -- a small group of scientists known in government circles as "the X-files Committee" -- warn that the earth is already overdue for a rendezvous large enough to extinguish ten percent of the population.
Such an asteroid strikes earth every 100,000 years, they argue, and by their measure it has been that long or longer since the last.
The odds are always great that we won't see that but it points up the need to pray. It's God Who has kept millions of pieces of space junk away from us. We have no idea what's really out there. As one of the foremost experts, Clark R. Chapman, said, a mountain-sized space rock big enough to dramatically alter global climate "could hit tomorrow and we wouldn't even know it was coming." Meanwhile David Morrison, head of NASA's asteroid program, adds that if something comes, the most likely warning time "would be zero."
"These long-period comets are always being found," Dr. Helin told me. "Just thank God they haven't come that close."